1. Field of the Invention
The present invention relates in general to automotive air conditioners, and more particularly to piping arrangements of the automotive air conditioners. More specifically, the present invention is concerned with a piping arrangement of a cooler unit of the conditioner, which can minimize the resistance against air flow in a housing of the cooler unit.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional piping arrangement of an automotive air conditioner will be briefly described with reference to FIG. 11 which is shown in Japanese Utility Model First Provisional Publication 63-96,918.
In the drawing, designated by 100 is a dashboard by which an engine room ER and a passenger room PR are bounded. A cooler unit housing 102 is arranged in the passenger room PR near the dashboard 100, which contains an evaporator 104. Air to be blown into the passenger room PR is forced to flow through a fin-unit face 104a of the evaporator 104. A first pipe unit 106 including a coolant inlet pipe 106a and a coolant outlet pipe 106b extends from a tank 104b of the evaporator 104. A second pipe unit 108 including a coolant inlet pipe 108a and a coolant outlet pipe 108b is connected to the first pipe unit 106 through a pipe joint 110. The second pipe unit 108 extends out of the cooler unit housing 102 to the engine room ER through an opening 112 formed in the dashboard 100. That is, the pipes 108a and 108b of the second pipe unit 108 are led to a condenser and a compressor respectively, which are both located in the engine room ER. An expansion valve unit 14 is connected to an exposed portion of the second pipe unit 108 in such a manner as to cover the opening 112 of the dashboard 100. Because the expansion valve unit 114 is not placed within the cooler unit housing 102, the air resistance in the cooler unit housing 102 can exhibit a satisfied low level.
However, in this conventional piping arrangement, usage of the second pipe unit 108 is necessary for connecting the first pipe unit 106 and the expansion valve unit 114, which induces not only increase in number of parts used but also difficulty in assembling the air conditioner.
Due to the inevitable shorter length of the first pipe unit 106, the hand work for connecting the second pipe unit 108 to the first pipe unit 106 tends to apply an abnormal stress to the portion where the coolant inlet and outlet pipes 106a and 106b are welded to the tank 104b of the evaporator 104.
Furthermore, in this conventional piping arrangement, the sealing at the opening 112 of the dashboard 100 is given little thought. In fact, in such piping arrangement, it is difficult to put the pipes 108a and 108b through the opening 112 with a satisfied sealing therebetween. As is known, if the sealing is not sufficient, noise in the engine room ER is easily transmitted to the passenger room PR.